arp head studs vs. head bolts
 

When is it necessary or a good idea to run head studs over head bolts? I ran arp head bolts last season no problem on my 383 on 200hp nitrous, but might run alittle more this year.

just do studs

The undercut ones right? 234-4401 for hex

M95Z -

You'll get alot of opinions here (such as mine below), but I think the best folks to ask your question to would be ARP.

Having said that, my car has used both ARP head bolts (in the past) and ARP head studs (currently) - I upgraded on my second rebuild.

However, the biggest issue (as it relates to cylinder pressure) in my OPINION is not the strength of the fasteners, but rather the strength / makeup of the head gaskets, as they tend to fail first.

I'm not a nitrous guy, but I can tell you that my Mr. Gasket MLS head gaskets and my ARP studs (with the nuts torqued to 77 ft - lbs) have had no problems keeping my 383 with 10.4 to 1 CR and all the boost and Meth I choose to throw at it (currently 12.5 psi) clamped down tight.

Now, my Felpro / stock style head gaskets - 4 psi tops.

Good luck!

imo its time to switch up. technically the bolt and stud are the same strength. the stud gives you a more accurate clamping force because of the fine treads vs coarse threads. and make sure you get 12pt nuts. big diameter springs will not allow you to get a socket on a 6pt nut.

felpro 1074's will take a lot more than you think. i have ran 8.90 at 153+ with them.

If re-machining the block I would consider studs the next time but I would not swap from bolts to studs when the block was machined and run with bolts. Bolts and studs distort the bore differently.

Not to stray off topic to say, but what is the cost difference between running studs or bolts?

96 is correct. Do not switch without honing the block with what you are going to use. I use ARP 12 point bolts because going through tear downs with studs in these cars is a pain. I take my bolts for one head. my torque wrench and a used gasket to the machine shop for honing. Use on the torque plate the same fasteners you are going to use on the heads. Be sure to have the guy that honed it tell you to what value he torqued them. Also what lube he used on the threads. This shit is much more critics than a couple degrees on the camshaft choice.
If you can find a shop with a Rottler Diamond Hone, use them instead of the old standby Summen automatic home. Patterson Racing if your close to Augusta KS, or Mike Trumble Racing Engines in Houston, Elite Motorsports in the OKC area are three I know of. The finish is criticle.

Hope this helps.

This info is gold and you just don't find it anywhere.

Thanks.

Thanks guys, my current bolts have been torque at least 5 times over the years. I will pick up some new bolts and call it good! Thanks Ed and everyone else!

I don't really agree with the diamond hones. I know a shop or two that uses them but if you go slow enough with a Sunnen stone setup the same thing can be achieved. Sunnen makes diamond stone hones too. I can see diamond hones in a shop that needs work done faster but I'm in no rush on a Sunnen.

The stones wear, I don't care how you do it. I know of at least two Pro Stock teams that changed to the Rottler and picked up power. (Hear of Mike Edwards? Long time friend of mine.) When Patterson changed to the Rottler my car picked up along with several of their customers I talk to. About the only guys that disagree still have an old Sunnen hone.
If they don't have and know how to use a profileometer, they are pissing in the wind anyway. The dial bore gauge that comes with the Sunnen hone makes them look really good. Only read in one thou increments. The sharp guys use a standard gauge that reads in tenths.
Depends on how fast your trying to go.

Diamond hone is definitely the future, but I'm still on a older SV-20. The stones do wear as you said, but for small volume you can get it really close. Modified the -20 to have a bottom dwell and always use a BHJ plate. I figure it's not the current racing standard, but it isn't too far off.

If you aren't doing competetive race engines I can't see replacing a Sunnen, or the older torque plates with all-the-same length bolts. The good torque plates use the same bolts or studs as the engine.

Being a little (?) anal about ring seal, I would do my street car the same way.

More power there than with a "custom" cam versus the correct off-the-shelf cam.

what ed said a couple posts back is exactly how I was going to respond to this thread

The Sunnen machine I have access to also has a ultrasonic thickness gauge and a profilometer. I use a torque plate, same head gasket, and same bolts. Stones wear, but with proper lubrication, stone loading, and stroke motion it turns out to be a pretty cylindrical shape at the end. Some people pass heated water through the block when they are honing to make it as close to operating parameters.

If honing with stones was so bad, why is that the accepted method for refurbishing hydraulic cylinders that operate at thousands of psi.

The Sunnen bore gauge I use goes to 10,000th of an inch.

Noice, Ed isn't saying it's a bad method, in fact he even said that he couldn't see replacing a sunnen if you have the right equipment. He's really just saying that there are better ways now...

Diamonds get you a better cut in less time, the new machines are a lot easier to use.

Studs for u.
 

Looks like u do quite a lot of racing and likely pop the heads more often than a DD. Studs make head R&R much easier. If your running NOx and a lot of racing i can image u would R&R the heads enough to make it worth it.

Good luck,
cardo